How do you guys level scopes?

[Snarf]

I think I might be going a tad overboard... but if I'm going to be working on Gunday, I am using some of my cycle time to play

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The scope has anti-tilt "bumpers" that warn you if you are past a threshold that you can set in the accompanying app, so I figured I want it pretty square. I don't usually use the scope with the illumination (and thus the BDC and all the other features) but I'm really still in the load development phase shooting almost entirely at 100 yards. In this case, with upper reciever bottom to top scope cap as my datums I'm out about .0005 over 3". Probably close enough.

I think the parts on the table behind my upper will be of some interest to those here, they are components of a system that mounts to the new JLTV (replacement humvee) and supports an M230 chain gun and a battery of sensors to detect and destroy small commercial drones - apparently before being bombed out of the 24hr news cycle, ISIS was using them in lieu of bomb vests. In tests it scored kinetic kills (direct hits) out to a half mile

[rabiddawg]

I set the rifle in a vice or holder and use a bubble level to get it level. Then I hang a plumb bob in front of my door. Then shine a flashlight from the objective end of the scope to project the reticle onto the door. Focus it by using the reticle focus ring. I put another level on the scope turret just for reference. Then I turn the scope until the vertical line and plumb bob are aligned. Snug down the rings and double check before torquing them down.

[Snarf]

I set the rifle in a vice or holder and use a bubble level to get it level. Then I hang a plumb bob in front of my door. Then shine a flashlight from the objective end of the scope to project the reticle onto the door. Focus it by using the reticle focus ring. I put another level on the scope turret just for reference. Then I turn the scope until the vertical line and plumb bob are aligned. Snug down the rings and double check before torquing them down.

That makes sense. That way you don't have to assume the scope turret cap is square to everything else. Just to satisfy my curiosity, do you ever come across a scope where you level against the plumb and get bad results from the level when you do your sanity check?

[A5BLASTER]

What I do for the ar now is I have a magpul pic rail mounted on my bench. I attach the one peice mount too it and torque it down. Then install the scope into the rings, put a bubble level on the elevation turret and level it, then tighten and torque down.

Remove from bench, install on rifle and never look back.

Seems too work great for me.

[Snarf]

Right on looks like that part of the setup is a solid "good enough." Now if we could just do something about that idiot behind the trigger...

[rabiddawg]

The only problem I have is making sure I tighten down the rings equally. If you go too far on one side it can cant the scope in the mount. I use a torque screwdriver and start way low.

[grayfox]

The only problem I have is making sure I tighten down the rings equally. If you go too far on one side it can cant the scope in the mount. I use a torque screwdriver and start way low.

yes. Use a torque wrench.
Back and forth on the screws, cross-over and back X-patterns, little at a time. watch the bubble level on the scope as you tighten each screw by each amount.
Also, I first do one ring, one pair of screws, to get it level and snug. then the other ring, one set of screws likewise. once both pairs of those are snug, do a "catch-up" on your remaining screws... then do the back and forth, cross over method a little at a time for all screws. Keep the bubble centered.
IIRC the bubble tends to move slightly away from the one you are tightening.

[Klem]

Put the gun in a rest, level the top Picatinny rail with a bubble, then rotate the scope in the rings until the vertical reticle lines-up with a plumb line downrange.

You can take a plumb line to the range you use regularly and confirm a permanent vertical structure downrange is plumb. Then use that to check scopes from then on - target frames, flag poles.

I use a 1m length of white PVC pipe suspended with a weight below it as a plumb line instead of string as it's easier to see without having to crank up the magnification.

[Kswhitetails]

I have an Arisaka optic leveling wedge set. It's great for quick painless leveling between the scope body itself and the optic mount or rail. It forces the body of the scope to be level in relation to the counterpart only, so I also use a bubble level and a known plumb line - in my case I go to the range with my tools and level the vertical reticle leg to the radio tower behind the target berms and set the level. That way, when the level shows plumb, I know I'm right, regardless of the position of the rifle. It gives me piece of mind that I'm not relying on the turret top to be perfectly perpendicular to the actual reticle, which while close, may or may not be as accurate as I want. We found that even a Khales 318 we tested was off a tad.

There are lots of top tier shooters that advise against using the top of the turret cap as a reticle level simply because some optics makers aren't machining the turret cap to be square, rather they focus on making sure the erector is correct, and the turret cap being perfect is an afterthought. I wonder if they're even tested to be in most lower priced optics.

[centerfire]

Scope caps are not square to the erector or the reticle. Square the bottom of the scope to the mounting base (Pic rail in this case), I use feeler gages but there's tons of ways to do it including a deck of cards. Once the scope is square to the rail go shoot the rifle. Scope mounted bubble levels are largely worthless and a waste of time. If you're concerned the reticle isn't square to the erector you'll need to shoot a tall target to tell how far out it is (unless it's visually noticeable).

[Kswhitetails]

The level isn't necessarily for leveling the reticle, it's to ensure that the sight radius from your point of aim is plumb to your bore axis. This matters, but just as you say centerfire, if the scope is square to the mount then you should be good to go.

[centerfire]

The level isn't necessarily for leveling the reticle, it's to ensure that the sight radius from your point of aim is plumb to your bore axis. This matters, but just as you say centerfire, if the scope is square to the mount then you should be good to go.

That wasn't what I was talking about but since we're on the subject, the plumbline is a waste of time too. How many AR uppers have you seen with a canted Pic rail? How about an R700? The only instance I can think of where the bore didn't match the base was a Remington with a receiver warped like a banana and you could see it with the naked eye. There is all kinds of scope mounting mumbo jumbo, and like everything else in shooting, it's over thought and makes no difference on the target down range. Again, level the scope to the base and shoot it.

[Klem]

Scope mounted bubble levels are largely worthless and a waste of time.

Why is that?

If you're concerned the reticle isn't square to the erector you'll need to shoot a tall target to tell how far out it is (unless it's visually noticeable).

What are the steps in this test?

[centerfire]

Why is that?

Because if you're holding the rifle canted enough to create error in your dialed elevation you can visually see the reticle is canted.

What are the steps in this test?

There's dozens of youtube videos on the subject.

[TomSawyerNW]

I've never leveled my scopes, and not saying that's a NOT good practice.

But how many of you level your scope and find it was significantly out-of-level to begin with?

For long range shooting, it's not difficult to understand the need to level the scope.